The present invention relates to a process for (electro-)depositing or coating a first layer of copper on a metal substrate surface and a second layer of chrome directly on the first layer, and to a component of valves, fittings or tap assemblies—preferably for plumbing and/or heating-plumbing purposes—obtained by means of such process.
Recent legislation has imposed the progressive elimination of nickel from tap and valve components having surfaces intended to direct contact drinking water due to the suspected toxicity of such metal. This requirement has already been adopted in some countries where the sale of valves comprising nickel is currently not recommended.
The problem of replacing nickel is a complicated task for manufacturers of the aforesaid components, as nickel is quite suitable for the subsequent depositing of chrome.
In fact, apart from nickel, very few metals offer surface coatings sufficiently hard so as to ensure duration of decades without suffering deterioration and are equally compatible with chrome so as to provide a product free of defects and qualitatively acceptable by the public.
Documents DE102010043046A1 and DE102005041375A1 describe processes for depositing chrome on a copper-plated metal component with solely decorative purposes. In particular, such processes require the presence of surfaces respectively overhanging or undercut so as to make patterns having an enhanced ornamental effect.
The prior document EP2460908A1 describes an electrolytic depositing of a layer of chrome on a substrate of a metal alloy of tin and copper, and subsequently the required protection of the layer of chrome by means of a precious metal such as gold, silver or platinum.
Document DE10223081A1 describes a procedure for covering a polymer body with a metalized layer by means of at least one non-electrochemical activation stage of such body.
Lastly, document EP1533397A2 describes a process for making a surface with an opaque effect, in the absence of nickel and chrome (VI).
The present invention falls within such context, providing a process for producing a final product with a degree of smoothness and shine at least comparable to that of products which comprise a nickel-coating.